1. Field of the Invention
The present invention relates to an embroidery frame of a type firmly holding a cloth between outer and inner subframes.
2. Description of the Related Art
In an embroidery sewing machine of a general type, a frame drive mechanism is driven to move a cloth-holding embroidery frame in X (right-and-left) and Y (back-and-forth) directions, respectively, so that any desired pattern is embroidered onto the cloth.
An exemplary embroidery frame for use with an embroidery sewing machine is found in JP-A-2002-315982. This embroidery frame is formed by a continuous-rectangular inner subframe, a rectangular outer subframe with a section that breaks the continuity, and a clamp mechanism for clamping the outer subframe against the inner subframe. With such a structure, the clamp mechanism includes two protrusion parts, and a screw member. The protrusion parts are respectively located at both sides of the continuity-breaking section of the outer subframe so as to face each other. The screw member is passed through a screw pass-through hole that is formed to the protrusion parts. To fix a cloth to such an embroidery frame, a user places the cloth between the inner and outer subframes of the embroidery frame. The user then uses his/her fingers to rotate an operation section of the screw member that is passed through the screw pass-through hole provided to the two protrusion parts of the outer subframe. Through rotation as such, the outer subframe is clamped against the inner subframe so that the cloth is firmly held thereby.
The problem with such an embroidery frame of JP-A-2002-315982 is that there is no enough space between the outer subframe and the operation section of the screw member. This is due to the placement structure of the screw member being parallel to the linear portion of the rectangular outer subframe. The outer subframe thus becomes an obstacle for the user to pinch the operation section between the thumb and fingertips, resulting in poor workability of the operation section in terms of rotation. This thus requires extra force to clamp the outer subframe against the inner subframe, especially enormous efforts to women who are the main users of the embroidery sewing machine.
When the user wants to fix a cloth to an embroidery frame on a table or others, such a placement structure of the screw member being parallel to the linear portion of the rectangular outer subframe causes another problem of limited accessibility for the space between the table and the operation section of the screw member provided to the embroidery frame. The upper surface of the table becomes also an obstacle for the user to rotate the operation section similarly to the above, and thus the user may bother to move the sewing machine to the position where the operation section protrudes outward from the table corner for clamping of the outer subframe. As such, it is difficult to increase the operation efficiency.